Electrochemical interaction behaviors between adjacent zinc-rich coating defects on steel structures under immersion and wet–dry environments

This study investigates the corrosion mechanism of carbon steel beneath zinc-rich coating (ZRC) defects to understand the mutual interference of carbon steel in atmospheric environments. First, electrochemical impedance spectroscopy (EIS) was conducted to determine the self-corrosion behavior of carbon steel under ZRC defects. Subsequently, a macrocell current tests were conducted under immersion and wet–dry environments to evaluate the electrochemical interaction effects at the location of coating defects. The results indicate that the electrochemical interactions between the ZRC defects are influenced by the sacrificial anode effect of Zn. Further, the interaction mechanisms between the steel substrates beneath the organic and inorganic ZRC defects were analyzed. The findings provide deeper insight into the behavior of steel structures in atmospheric environments, offering potential improvements in the design of protective coatings for infrastructure longevity.